Obesity is an important risk factor for many aging-related conditions such as type 2 diabetes, cardiovascular disease, cancer, injuries, physical function disabilities, and premature mortality. Obesity risk can be established early in the life course. Socioeconomic disadvantage and other forms of social adversity occurring prenatally and during early childhood substantially increase risk for obesity in adulthood. This has profound implications for efforts to reduce morbidity associated with obesity-related conditions. A major unresolved question is whether or not obesity risk initiated in childhood can be altered by interventions in adulthood. If so, then it is critical to identify modifiable intervention targes. Modifiable intervention targets are by definition factors that lie along the causal pathway linking early life adversity to obesity in adulthood (i.e. that mediate the link between risk and disease). To expand knowledge of etiology, all such mediators are of interest. For public health purposes, we are most interested in mediators with the strongest effects, as intervening on these mediators will provide the most impact in the effort to reverse the long-term effects of early adversity on adulthood obesity. There is surprisingly little known about whether major candidate factors such as diet, physical activity, smoking, depression, education and epigenetic methylation patterns mediate the links between early life adversity and adulthood obesity. Consequently, we propose the following specific aims, focusing on two primary clinically relevant measures of adiposity in adulthood, specifically body mass index and waist circumference: (1) To investigate the roles of socioeconomic, behavioral, and mental health factors in the associations between childhood economic disadvantage, social adversity and adult adiposity. (2) To determine if there are epigenetic DNA methylation mediators of the associations of childhood economic disadvantage and social adversity with mid-life adiposity. The proposed aims will be achieved using unique data and biosamples from the New England Family Study, a long-term follow-up study of births from the Providence, RI and Boston, MA cohorts of the Collaborative Perinatal Project, born between1959-1966. There are few prenatal cohorts in the world with directly assessed social exposures from pregnancy through the first 7 years of life. We propose to perform Infinium HumanMethylation450 BeadChip DNA methylation arrays on stored adipose and leukocyte samples for a sample of 68 males and 68 females with epigenetic profiles. Cardiovascular and other demographic variables were directly assessed in 831 participants during the years 2005-2011 at age range 42- 50 years. We will employ sophisticated causal mediation analyses to estimate the comparative effects of the conditions we hypothesize to be potential intervention targets. The results of the proposed study will provide new etiologic insights regarding the pathways linking early adversity to obesity in adulthood, and will provide evidence regarding the anticipated benefits of interventions on a wide range of potential targets to reduce the long-term consequences of early childhood adversity on obesity.